LEASES - Right-of-use lease assets and lease liabilities (Details) - USD ($) $ in Thousands	Jun. 30, 2020	Sep. 30, 2019
Right-of-use lease assets and lease liabilities
Operating lease right-of use-assets, net	$ 4,272	$ 0
Current portion of operating lease liabilities	874	0
Long-term operating lease liabilities	3,733	0
Total operating lease liabilities	4,607
Finance right-of-use assets, net	4,628	0
Current portion of finance lease liabilities	4,557	18
Long-term finance lease liabilities	53	$ 18
Total finance lease liabilities	$ 4,610